INDUCTION, MAINTENANCE AND RECOVERY CHARACTERISTICS OF DESFLURANE IN INFANTS AND CHILDREN

To determine the induction and recovery characteristics of the new poly-fluorinated anaesthetic desflurane, 78 fasting and unpremedicated neonates, infants and children up to 12 yr of age were studied. Patients were stratified according to age: full-term neonates < 28 days of age (n = 12), infants 1-6 mth (n = 12) infants 6-12 mth (n = 15), children 1-3 yr (n = 15), 3-5 yr (n = 12), and 5-12 yr (n = 12). After preoxygenation for two minutes and an awake tracheal intubation, neonates were anaesthetized with stepwise increases in the inspired concentration of desflurane in an air/oxygen mixture. Infants 1-12 mth of age and children were anaesthetized with stepwise increases in the inspired concentration of desflurane in oxygen. Their tracheas were intubated under deep desflurane anaesthesia without muscle relaxation. The incidence of airway reflex responses (including breathholding, coughing, laryngospasm, bronchospasm and oropharyngeal secretions), incidence of excitement, minimum arterial oxygen saturation, and times to loss of eyelash reflex and tracheal intubation during induction were recorded. After skin incision, anaesthesia was maintained with desflurane (almost-equal-to 1 MAC) in 60% nitrous oxide and oxygen. Heart rate and systolic arterial pressure were recorded awake, at almost-equal-to 1 MAC before and after skin incision and throughout surgery. At the completion of surgery, all anaesthetics were discontinued and the lungs were ventilated with 100% oxygen. During emergence, the end-tidal concentration of desflurane was recorded until extubation. The incidence of airway reflex responses and the times to eye opening and extubation after the discontinuation of desflurane were recorded. We found that during induction of anaesthesia, breathholding occurred in 50% of patients, coughing in 36%, moderate or severe laryngospasm in 30% and secretions that required suctioning in 7.6%. Excitement occurred in 100% of infants and children. Arterial oxygen saturation (mean +/- SD) decreased to < 90% in 18% of children. The time (mean +/- SD) from commencement of desflurane to loss of the eyelash reflex was 1.2 +/- 0.4 min and to tracheal intubation, 4.6 +/- 1.2 min. Heart rate and systolic arterial pressure were stable throughout surgery. The washout of desflurane did not differ among the six groups. FA/FAO was 0.14 +/- 0.05 at two minutes and 0.06 +/- 0.04 at five minutes after discontinuation of desflurane. The time from discontinuation of desflurane to extubation was greater in neonates, 6.6 min, than it was in older infants and children, 4.5 to 5.8 min, after approximately 45 min of surgery (P < 0.05). None of the patients demonstrated airway reflex responses after extubation. We conclude that although desflurane is not suited for induction of anaesthesia in infants and children, it maintains haemodynamic stability during surgery and facilitates a rapid recovery of consciousness without triggering airway reflex responses.